/Engine/Source/Runtime/GeometryCore/Public/CompGeom/ConvexHull3.h
Useful helper for walking the border of a convex region, or of a QHull horizon. Will also work for extracting a group boundary for any closed triangle mesh. Note: Assumes TriangleNeighbors are listed such that the first neighbor is the tri across from the (Tri.A, Tri.B) edge
static void WalkBorder ( const [TArray](API\Runtime\Core\Containers\TArray)< [FIndex3i](API\Runtime\GeometryCore\FIndex3i) > & Triangles, const [TArray](API\Runtime\Core\Containers\TArray)< [FIndex3i](API\Runtime\GeometryCore\FIndex3i) > & TriangleNeighbors, [TFunctionRef](API\Runtime\Core\GenericPlatform\TFunctionRef)< bool(int32)> InGroupFunc, int32 StartIdx, [TArray](API\Runtime\Core\Containers\TArray)< int32 > & OutBorderVertexIndices )